10
INSTALLATION INSTRUCTIONS
J. THERMAL EXPANSION
WARNING:
The water heater should not be installed in a space where liquids which give o ammable vapors are to be used or
stored.
Determine if a check valve exists in the inlet water line. It may have been installed in the cold water line as a
separate backow preventer, or it may be part of a pressure-reducing valve, water meter or water soener. A check
valve located in the cold water inlet line can cause what is referred to as a “closed water system.” A cold water inlet
line with no check valve or backow prevenon device is referred to as an “open” water system.
As water is heated, it expands in volume and creates an increase in the pressure within the water system. This acon is
referred to as “thermal expansion.” In an “open” water system, expanding water which exceeds the capacity of the
water heater ows back into the city main where the pressure is easily dissipated.
A “closed water system,” however, prevents the expanding water from owing back into the main supply line, and the
result of “thermal expansion” can create a rapid and dangerous pressure increase in the water heater and system
piping. This rapid pressure increase can quickly reach the safety seng of the relief valve, causing it to operate during
each heang cycle. Thermal expansion, and the resulng rapid and repeated expansion and contracon of
components in the water heater and piping system, can cause premature failure of the relief valve, and possibly the
heater itself. Replacing the relief valve will not correct the problem!
The suggested method of controlling thermal expansion is to install an expansion tank in the cold water line between
the water heater and the check valve (refer to the illustraon on right). The expansion tank is designed with an air
cushion built in that compresses as the system pressure increases, thereby relieving the over-pressure condion and
eliminang the repeated operaon of the relief valve. Other methods of controlling thermal expansion are also
available. Contact your installing contractor, water supplier or plumbing inspector for addional informaon regarding
this subject.
K. FILLING WATER
WARNING:
The unit must be COMPLETELY lled with water before being turned on. Failure to do so may permanently damage the
unit and will VOID manufacturer’s warranty. To check if the tank is full:
a. Ensure drain valve is shut ghtly
b. Open cold water inlet valve to ll the tank
c. Open hot water faucets slowly to allow air in the tank and piping to vent out
d. Smooth, undisrupted ow of water from the faucets indicates that the tank is full.
Turning the unit on when the tank is not completely full with water will cause water temperature to rise quickly and
trigger an alarm. If the alarm is triggered, turn the unit o and re-check that the tank is completely lled with water.
CONSUMER
SUPPORT MAINTENANCE OPERATING
INSTRUCTIONS
INSTALLATION
INSTRUCTIONS
SAFETY
INFORMATION
